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,UNITED STATES:

' HENRY W. MERRITT, or BOSTON, MASSACHUSETTS, ASSIGNOR To WILLIAM I V H. IRELAND, OF SAME PLACE. o

PLASTIC COMPOUND FQR WALLS, 80C.

SPECIFICATION forming part of Letters Patent No. 322,307, dated July 14, 1885. V

' Application filed May 4, 1885. (No specimens.) I

To all whom it may concern:

' 1 Be it known that I, HENRY W. MER'RITVT,

and become extremely hard. Such plastic compound is especially useful as a plaster for coating the walls of buildings, and it needs no v hair or fibrous material intermixed therewith to make it cohere. Moreover, it can be made to adhere with great tenacity to the surfaces of wood, masonry, or glass, and thus form an enduring covering thereon.

I will first describe the best mode which I have discovered for practicing my invention, and will then explain its nature and scope.

7 There is known in the market a highly-silicious substance called asbestine which'is rin i all asilicate of ma neslum. It exls't's as a natural mineral deposlt in St. Lawrence county, New York. Its composition has been found by analysis to be, silica, 61.23 per cent.; magnesia, 31.37 per cent.; alumina, 1.99 per cent.; iron protoxide, 0.37 per cent., and water, 5.02 per ,cent.; but of course the percent- 7 age of silica, magnesia, and associated substances may be expected to vary somewhat in different specimens.

I- have found that when asbestine is reduced to powder and mixed with quartz-sand and s5 ceg iqaqdasacausticP9121 1 dissolved in ter tlire may be formed aplastic mass which can be worked and applied like mortar, and

. which, when spread and exposed to the air,

turns as hard as a stone without tendency to For this purpose I take tygeptypounds of iowdered asbestine forty pounds ofuartz=sam an one an one-half 'pound of caustic soda. These ingredients are then worked lntQ'a plastic mass by the use of 5 about twenty-two pounds of water, in which the caustic alkali is first disso vec and then 1 the powdered asbestine and sand are introduced and thoroughly intermixed. 'The proportions of these ingredients here given are not absolute, but may be-varied somewhat within practical limits, which will be readily PATENT understood from the explanations herein contained. The plaster adheres well enough to ordinary lathi'ng or rough surfaces; but when it is intended to be spread upon smooth surfaces I find that a small proportion of soluble silicate of soda may be advantageously introuce 0 ma 'e he mass more adhesive. For this latter purpose I find that about three and one-half pounds of the soluble alkaline sili-'6o cate in the mass already specified is snfiicient. Chemically considered, it appears that this stone-like plaster results from a combination effected between the silicate of magnesium and the sand (silica) by'the agency of the caustic alkali after these ingredients are brought together and incorporated in the presence of water. I have found that y'arious solid sili- 5 cates in a pulverlzefl state possess this ca abill o combination with comminp te d silica -by means of vfixed cans .10 a 'a 1-6. e., caustic soda or caustic potaslid1ssolved in water so f- I ficient to enable the dry ingredients. when T silicates of magnesium and also, silicates of minum, silicates of calcium, and, in general,

highly silicions. Such solid silicates are soluble in water.

eral deposits I have tried as substitutes for ser entine soao'ston and asbestusand I have found em 0 answer the purpose measurably well. The solid silicates of other bases appear to be for this purpose inferior to the silicates of magnesium; but for the sake of 0 economy fairly good results may be attained by mixing such other silicates with asbestine; nor need thesand used be pure silica, although it must be silicious, and it will be chemically effective only by reason of the silica present 95 in it. Thus ipfusoaiql earth and eveuptm may be su s 1 u e or sand or intermixe therewith,and useful, although inferior, results be attained; but this will rarely be done on account of the abundance of good too quartz-sand. From what I have said it willbe understood Examiner tlrigpggwntemmxod therewith to form a p astlc mass. Of these I may men 11011 0t e f-"7 magnesium and aluminum, silicatesof alu- Y l solid silicates of simple or compound bases, more particularly those silicates which are .Among the naturalsilicates existing as min- 7 v I asbestine various other substances such as dients silica and a solid silicate, each in comthat along with the effective ingredients of my plastic compound-to wit, silicate of magnesium or other highly silicious solid silicate in a pulverized state, quartz-sand or comminuted silica and fixed caustic alkali either wither withoiTt'a solu Jle alkaline silicateere ue associated either chemica l'l'y bi mechanirally other substances in quantities more or less considerable without practical detriment to the resulting stone-like material obtained by exposure of such plastic compound to the air. Nevertheless, I do not recommend the use of such foreign substances nor of the inferior substitutes for asbestine and sand to which I have referred. I have mentioned them only to illustrate the scope of my invention,and to show that its benefits may be measurably attained even when it is not practiced most advantageously; I have also found that all the ingredients of my new plastic conr, pound except the sand may be mixed together and kept for future use at the places where it may be convenient to add the sand. This .mixturelof pulverized solid silicate, fixed alkali, and water, either with or without a proportion of soluble alkaline silicate, can be put in barrels and transported,ready for the addition of the sand, wherever it may be desired to make the plastic compound which is to harden into artificial stone. Such mixture of itselfis new, and it is part of my invention to prepare it separately for subsequent use with comminuted silica to form my new plastic compound. v r

I claim- 1. A plastic compound containing as ingreminuted or pulverized condition, and fixed caustic alkali dissolved in water, the whole being intermixed and incorporated substantially as described.

-2.'A plastic compound consisting of silica and a solid silicate, each in comminuted or pulverized condition, fixed caustic alkali dissolved in water, and a soluble alkaline silicate, the whole being intermixed and incorporated substantially in the manner and for the purpose set forth.

3. A plastic compound containing as ingredients comminuted silica, a solid silicate of magnesium in pulverized state, and fixed caustic alkali dissolved in water, substantially as described.

4. A plasticcompouud consisting of quartzsand, pulverized asbestine, and caustic soda 55 or caustic potash, with water to dissolve the alkali and give plasticity to the mass. 5. A plastic compound consisting of quartzsand, pulverized asbestine, caustic soda or l caustic potash, and a soluble alkaline silicate,

with water to dissolve the soluble ingredients and render the mass suitably plastic.

6. A mixture of pulverized solid silicate, fixed alkali,and water, either with or without a proportion of soluble alkaline silicate, ready 65 MERRITT. 

